Fluid apparatus



May 16, 1961 T. BUDZICH FLUID APPARATUS 2 Sheets-Sheet 1 Filed NOV. 27,1959 INVENTOR. TADEUSZ BU DZ I CH BMW May 16, 1961 T. BUDZICH 2,984,223

FLUID APPARATUS Filed Nov. 27, 1959 v 2 Sheets-Sheet 2 FIG. 2

INVENTOR. TADEUS Z BUDZI CH y/fMMM W FLUID APPARATUS Tadeusz Budzich,3344 Colwyn Road, Cleveland, Ohio Filed Nov. 27, 1959, Ser. No. 855,559

12 Claims. (Cl. 121-121) The present invention relates to fluid pressureenergy translating devices of the piston pump or motor type, and hasparticular significance in connection with fluid piston pumps and motorsemploying a stationary cylinder barrel and a rotary cam plate driving arotary valving means which sequentially conducts fluid to and frommultiple cylinders of the stationary cylinder barrel.

In general, piston pumps and motors employing a nonrotating cylinderbarrel are operative at much higher speeds than rotating barrel typesdue to the absence of centrifugal forces acting on the pistonassemblies. In both types with a properly supported and universallymounted cylinder barrel, capable of aligning itself to a valve plateequipped with a kidney-shaped fluid conducting passage of the typewell-known in the art, high volumetric and mechanical efiiciencies canbe obtained. To make valving possible, many ingenious devices have beenused in the past to support the cylinder barrel in such a way as toeliminate the influence of the piston forces and make it free floating.One well-known method of balancing barrel to valve utilizes smallkidney-shaped slots in the face of the cylinder block and incommunication with the pump cylinders. Due to the requirements ofbalance, the area of such slots must be substantially smaller than thecross-section area of the pistons, resulting in severe fiow losses andinlet throttling. At the same time, the machining of such kidney shapedslots is very expensive, and usually results in loss of dimensionalaccuracy.

It is an object of the present invention to provide inexpensive meansfor overcoming the above mentioned difficulties.

Another object of the invention is to provide a rotary valving meanscapable of aligning itself to the end face of a stationary cylinderbarrel.

A further object is to provide rotary valving means with hydrostaticallybalanced distribution surfaces resulting in minimum mechanical andvolumetric losses.

A further object is to eliminate substantially all forces associatedwith introduction of high pressure fluid to a rotary valve thus toreduce bearing pressure on sealing surfaces.

A further object is to provide a rotary valve plate of a balancedself-aligning type capable of working in contact with circular openingsof straight through cylinder bores thus providing a lower cost and moreaccurate construction while eliminating a flow loss and permittinghigher speed of operation with minimum inlet and outlet throttling.

Other objects and advantages will become apparent and the invention maybe better understood from consideration of the following descriptiontaken in connection with the accompanying drawings, in which:

Fig. 1 is a sectional elevation of a fluid pump or motor embodying thepresent invention, but with valve plate rotated by 90 from its workingposition;

Fig. 2 is an end view of cylinder barrel taken on the liilekZ of Fig. 1;

nited States Patent Fig. 3 is a mating end view of valve plate takenalong the line 3--3 of Fig. 1; and

Fig. 4 is an end view of balancing plate taken on the line 4--4 of Fig.1.

Description Although the illustrated device will be described as a motorit can Work equally well as a pump. A housing body 10 is closed at oneend by an end cover 11 and at the other end by a valve cover 12 bothsecured by bolts not shown. Formed integral with housing 1% is acylinder barrel equipped with circumferentially spaced longitudinalbores 13 in which pistons 14 are slideably mounted for reciprocation.Pistons 14 have part-spherical ends 15 with swaged over universallymounted piston shoes 16 which work in contact with a fiat faceof a camplate 17 and are axially restrained from leaving this flat surface by anutating plate 13. This cam plate is mounted for rotation with respectto the housing cover by bearings 19 and drives an external shaft 241. Ashaft seal 21 is provided between shaft and cover and, as thus fardescribed, the arrangement may be considered more or less conventionalexcept that the cylinder bar rel is an integral part of the outerhousing. A central shaft 22 is at one end in splined engagement with camplate 17 and at the other end terminates in a reaction piston 24 whichcarries a sealing ring 24'. Piston 24 has a piston flange portion 24" bywhich it is mounted with respect to the cylinder block by needle thrustbearings 25.

The associate (valve plate mating) end 26 of the cylinder block isprovided with circumferentially spaced openings 27 leading to thecylinder bores 13 (and in accordance with one aspect of the presentinvention these openings are of the same size as, or merelycontinuations of, said bores). End face 26 is also provided withcircumferentially spaced shallow recesses 23 (outside) and 29 (insidethe circle of centers of cylinder openings 27) which shallow recessesare located angularly midway between cylinder bores (see Fig. 2).

A valve plate 30 (see Fig. 3) is secured with respect to the reactionpiston 24 by a pin 31, and is thus secured for rotation with the camplate 17 and shaft 20. A portion of the valve plate 30 is dispensed with(so as not to impede discharge fluid) and the missing part ismechanically compensated for by a weight moment 32.

The valve plate has a kidney-shaped timing slot 34 for sequentiallymating with the various cylinders 13, and this slot 34 is connected by aseries of drilled passages 35 with a central passage 36. In accordancewith the present invention the slot 34 extends right through the valveplate to connect the registering cylinder bores 13 with openings 41communicating with cylinders 42 in a balanc ing plate 43 (see Figs. 1and 4).

The valve plate central passage 36 at one end terminates in a cylinderbore accommodating the reaction piston 24 and its sealing ring 24', andat the other end passage 36 terminates in a circular face which works inoperational contact with a balancing lip of a high pressure sleeve 45which is mounted with partial universal freedom in a cylindrical hole 46provided adjacent a high pressure port 47. The high pressure sleeve 45carries a sealing ring 45.

The balancing plate 43 flat face equipped with circular passages 41leading to balancing cylinders engages a face of the valve plate.Balancing plungers 48 work in sliding engagement within the balancingcylinders 42 and are provided with part spherical heads 49 for engaginga flat face 50 of the end cover or housing. The balancing plate 43 isprevented from rotation by a pin 51 which acts in a clearance to permitaxial movement of balancing plate and partial freedom of angularalignment. A compression spring 52 is interposed between the cover 12and flat face of the balancing plate.

the balancing plate 43 to maintain the balancing plate in contact withthe valve plate and the valve plate in contact with the cylinder blockduring starting. Like the flat face 26 of the cylinder block, the (valveplate mating) face of the balancing plate 43 is equipped with shallowcircular curved depressions 58, 59 located angularly at I Operation Asshown in Fig. 1, the cylinder barrel is formed as an integral part ofthe pump housing and contains a series of horizontally extendingcylinder bores in which the motor pistons are arranged to reciprocate.The motor pistons with their part-spherical ends equipped with pistonshoes work in operational contact with the inclined face of the camplate and are maintained on the low pressure stroke in contact therewithby the nutating plate engaging flange ends of the piston shoes inwell-known manner. High pressure oil from the valve plate is conductedthrough passages (not shown) extended along the axes of the pistons tobalancing surfaces of the piston shoes in known manner. With the unitacting as a motor and with pistons subjected to hydraulic pressurelocated on one side of the principal axis, due to the action of theinclined plane rotational motion will be induced in the cam plate and itrevolves while supported by the antifriction bearings. The cam plate andthe valve plate rotate in timed relationship because connected by thetiming shaft 22 and pin 31. For the unit to operate as a motor, all ofthe pistons subjected to pressure are cated on one side of the principalaxis of the cam. Actually the valve plate as shown in Fig. 1 for thepurposes of demonstration of valve plate construction is not in itsusual position but rotated by 90. It should be noted that with theangular relationship between the valve plate and the cam plate shown inFig. l the motor would be inoperative, an approximately equal number ofcylinders and pistons under pressure being located on each side of theprincipal axis of the cam. But with the 90 rotation suggested thisdifliculty is corrected.

With the construction herein illustrated and described the cylinderbarrel, being part of the housing, is incapable of aligning itself tothe valve plate for maximum volumetric and mechanical efficiency.Therefore, the valve timing slot extends right through the valve platebetween parallel surfaces one working in contact with the flat face ofthe cylinder barrel and the other in contact with Thus the timing slotconnects the cylinder bores of the motor with the openings in thebalancing plate leading to the balancing cylinders housing the balancingplungers while the timing slot is also connected by the series of radialdrillings to the central passage of the valve plate terminating at oneend in the cylinder housing the reaction pistons and at the other end ina flange which with its fiat face works in operational contact with thehigh pressure sleeve communicating with the high pressure port. The highpressure sleeve cross-section is subjected to the high pressure oil athigh pressure port end. The other end of the high pressure sleeve hasits balancing land engaging the flat surface of the flange surroundingthe central passage of the valve plate. These two parts are maintainedin contact by the resultant hydraulic force induced by the differencebetween the area of the high pressure sleeve subjected to high pressurein high pressure port and the The end cover area subjected to highpressure on the opposite side of the sleeve as enclosed by the balancingland plus the leakage pressure equivalent acting on this balancing land.Although the contact pressure between valve plate and high pressuresleeve is by proper balancing reduced to bare minimum the valve plate isstill subjected to the full force equal to the cross-section area of thehigh pressure sleeve exposed to the high pressure port. This force wouldnormally induce very high bearing loads between valve plate and flat endof the cylinder barrel. To eliminate or modify this force the reactionpiston is introduced and located in the central passage opposite thehigh pressure sleeve. It should be noted that the area of the reactionpiston is equal to the area established by the CD. of the portion of thehigh pressure sleeve extending into the high pressure port. In this waytwo equal and opposite forces acting on the valve plate cancel eachother and the valve plate is permitted to align itself to the front faceof the cylinder barrel under the action of balancing forces coming fromthe balancing plungers as explained hereafter. Meanwhile the highpressure oil acting on the reaction piston produces force on thereaction piston which must be carried by some means. In the illustratedembodiment this force is carried on small anti-friction bearingspositioned between the flange of the reaction piston and the pumphousing. This force might have been carried to the bearings supportingthe cam through the splined shaft, but in any event it is preferable tohave the valve plate engage the piston in a slideable manner, as shown,so that small axial movements of valve plate are possible.

The purpose of balancing of surfaces of valve plate is to providestationary and revolving mating surfaces with the fluid pressure sodistributed on the areas in contact that these surfaces can carry largeloads with very low bearing pressures and therefore low mechanicallosses at relatively high rotational speeds. In the case of aconventional solution with aself-aligning cylinder barrel (eitherrotating or stationary) working against a fiat surface of a valve plate,the load carried on hydrostatically balanced sealing surfaces is equalto the total combined area of the pistons subjected to pressure by thedischarge or inlet pressure. This force then must be partially balancedby the fluid pressure distribution on the valve plate in contact withthe cylinder barrel so that only a fraction of the total force holds thecylinder barrel against the valve plate preventing separation andreducing leakage at minimum mechanical losses. This immediately dictatesthe size of the balancing areas and therefore the width of the kidneyshaped slot connecting the cylinder bores with the high pressure portand the width of sealing and balancing lands surrounding said slot.Therefore with the timing slot width substantially smaller than thecylinder bore diameter, placing of mating small kidney shaped slots inthe end of the cylinder barrel has heretofore seemed necessary. Thisconstruction is not only more expensive (as compared with straightthrough bores) but it also makes the cylinder barrel longer since thepistons cannot approach the working surfaces between the cylinder barreland the valve plate. Such obstructions at the end of the cylinder barrelalso provide substantial flow losses at high speeds of operation of theunit inducing torque losses and limiting the maximum speed.

.With the valve plate construction as shown in Fig. l the process ofbalancing is reversed. With the present invention each cylinder bore canrun through to the flat face of the cylinder barrel in contact with thevalve plate. The width of the timing slot may then be selected forminimum losses with the maximum operating speed. Advantageous sealingand the balancing lands may then be placed around the timing slot; withouter and inner radii of these lands overlapping cylinder bore openings.

This construction results in very large loads induced by the combinedeffects of timing slot area, area of the cylinder bores and the pressuredistribution due to pressure gradient acting on sealing landssurrounding the timing slot. To partially reduce these loads the seriesof curved shallow depressions may be placed in the spaces betweencylinder bores. These depressions are located radially away from theouter and inner edges of the timing slot and therefore define the widthof the sealing lands between individual cylinder bores. At the same timethese shallow depressions not only reduce the hydraulic loads acting onthe valve plate but provide dirt traps to prevent scoring and damagingof the sealing surfaces.

In accordance with one aspect of the present invention the valve plateis equipped with two identical parallel faces with the second facemating with a surface of the balancing ring in which circular openingsof the same diameter as the main cylinder bores are located opposite themain cylinder bores. In this way two parallel surfaces of the valveplate are subjected to identical loads caused by identical pressuredistribution. The balancing plungers, working in balancing cylinderslocated in balancing plate, are of larger diameter than the maincylinder bores and thus provide a positive force maintaining the facesof the valve plate in contact with the cylinder barrel and the balancingplate. The diameter of the balancing plungers is so arranged that theexcess holding pressure preventing separation is at a minimum forproducing satisfactory sealing with minimum of mechanical losses.Preferably the center of each balancing plunger is located substantiallynear the center of pressure acting on a segment enclosed by imaginarylines passing from the center of rotation midway between cylinder bores.The balancing plungers with their part-spherical ends engage the flatsurface of the motor cover and being slideably mounted in relation tothe balancing plate provide a freedom of alignment of balancing platewith respect to valve plate. A keying pin secured in the cover preventsrotation of balancing plate and because of a clearance hole allows it alimited freedom of alignment. The sealing surface extending all aroundthe timing slot 34 encompasses all the ports of cylinder bores subjectedto pressure while all the ports of cylinder bores subjected to lowpressure are in direct communication with the cylindrical space providedin the end cover and thus with the low pressure port. With the balancingprincipal employed as described above, and with total elimination by useof a reaction piston of the force disturbance caused by introduction ofhigh pressure oil to the valve plate, as described above, a floating andself aligning condition is achieved resulting in minimal losses, bothmechanical and volumetric, while the machine can be employed at veryhigh speeds.

While I have illustrated and described a particular embodiment, variousmodifications may obviously be made without departing from the truespirit and scope of the invention which I intend to have defined only bythe appended claims taken with all reasonable equivalents.

I claim:

1. In a fluid pressure energy translating device of the type comprisinga stationary cylinder block having a plurality of cylinder bores,pistons mounted for reciprocation in the cylinder bores, a cam plateoperatively associated with reciprocation of the pistons, and a valveplate rotatable with respect to the cylinder block, said valve platehaving two parallel faces with a port extending through the valve plateand through said faces to communicate at one end thereof sequentiallywith openings leading to the cylinder bores, a balancing platecontacting the second of said parallel faces, said balancing plate beinggenerally non-rotatable while free to move axially a'n'd tiltingly, saidbalancing plate having openi'ngs adjacent said second face, saidopenings leading to balancing cylinders within the balancing plate,fluid pressure plunger means slideable located in said balancing platecylinders so that the fluid pressure plunger means are associated withopenings communicating with said valve plate port at its end oppositethe cylinder block for aligning valve plate with respect to cylinderblock, and pressure fluid conducting means establishing communicationwith said valve plate port to and from the outside of the device, thecenters of the openings leading to the balancing cylinders in thebalancing plate being substantially co-axial each with a center of anopening leading to a cylinder bore in the stationary cylinder block.

2. The combination of claim 1 further characterized by an outer housingassembly and by the fluid pressure plunger means comprising a pluralityof plungers each having a part-spherical head contacting an innersurface of said housing assembly for reaction while providing limitedfreedom of alignment to enable balancing plate to mate with valve plate.

3. The combination of claim 1 further characterized by the cylinderblock having a face containing the openings for communicating with thecylinder bores, said face having shallow depressions located angularlymidway between the openings communicating with the cylinder bores whileradially displaced therefrom and partially overlapping the contact landon the adjacent face of the valve plate while not overlapping the valveplate port, whereby to reduce balancing loads.

4. The combination of claim 3 further characterized by the balancingplate surface adjacent the valve plate having similarly located shallowdepressions.

5. The combination as in claim 1 further characterized by the valveplate having a central passage which is generally coaxial with thecylinder block, and the valve plate having plural radial drillingsconnecting said passage with the valve plate port, a non-rotating highpressure sleeve having one end in operational contact at one side of thevalve plate and establishing communication with said central passagethrough said sleeve, an outer housing portion having a high pressureport communicating with the other end of said sleeve, a reaction pistonlocated at the opposite side of the valve plate and having a faceadjacent the central passage thereof with the diameter of the effectivearea of said piston face being equal to the area defined by the outerdiameter of the high pressure sleeve portion exposed to the highpressure in the high pressure port, whereby to eliminate the forcesotherwise exerted on the valve plate by the high pressure sleeve andreduce bearing pressures and maintain freedom of alignment of valveplate With respect to cylinder block.

6. The combination as in claim 5 further characterized by the sleevehaving predetermined dimensions of end faces such that the sleeve iskept in contact with the valve plate by a positive force.

7. The combination as in claim 5 further characterized by a thrustbearing interposed between reaction piston and cylinder block.

8. The combination of claim 7 further characterized by the reactionpiston being slideably mounted in an opening in the valve plate andkeyed to said valve plate to permit torque to be transmitted from one tothe other without affecting limited freedom of axial movement of valveplate with respect to piston.

9. The combination of claim 8 further characterized by the reactionpiston having a stem terminating in splined engagement with the valveplate so that valve plate will rotate responsive to rotation of camplate.

10. In a fluid pressure energy translating device, a stationary cylinderbarrel arranged in annular form about a central axis and having aplurality of cylinder bores extending parallel to said axis andterminating with full 15 diameter in end surfaces of said barrel,pistons mounted for reciprocation m the cylinder bores, a rotatable camplate operatively associated with reciprocation of the pistons andlocated at one end of ,the cylinder barrel for rotation about said axis,a rotatable valve plate located at the opposite end of the cylinderbarrel for rotation about said axis, said valve plate having a port andone surface surrounding said port, with said surface and port operativeagainst an end of the cylinder barrel in which end the cylinder boresterminate with full diameter, and a fluid pressure operated balancingplate to maintain contact between valve plate and cylinder barrel.

11. The combination of claim 10 further characterized by the balancingplate having cylinders containing fluid operated plungers equal innumber to the cylinder barrel pistons but of a uniform diameter largerthan that of said pistons while the balancing plate cylinders terminatein openings adjacent the valve plate which openings have a uniformdiameter substantially equal to that of the cylinder barrel cylinderbores and are coaxial therewith, whereby to keep the valve plate incontact with the cylinder barrel and the balancing plate in contact withthe valve plate to provide minimum leakage and minimum horsepowerlosses.

supporting said reaction piston from one end of the cylinder barrel forminimizing the forces from the high pressure sleeve while maintainingthe free floating and self aligning characteristics of the valve plateand providing minimal losses.

References (fitted in the file oi this patent UNITED STATES PATENTS1,842,569 Richer Jan. 26, 1932 2,406,138 Ferris et a1. Aug. 20, 19462,620,736 Overbeke Dec. 9, 1952 2,661,701 Ferris Dec. 8, 1953 2,674,197Dudley Apr. 6, 1954 2,861,552 Creighton et al. Nov. 25, 1958

